futex: Simplify fixup_pi_state_owner()

commit f2dac39d93987f7de1e20b3988c8685523247ae2 upstream

Too many gotos already and an upcoming fix would make it even more
unreadable.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/futex.c b/kernel/futex.c
index fe83273..0f61be7 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2331,18 +2331,13 @@ static void unqueue_me_pi(struct futex_q *q)
        spin_unlock(q->lock_ptr);
 }
 
-static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
-                               struct task_struct *argowner)
+static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+                                 struct task_struct *argowner)
 {
        struct futex_pi_state *pi_state = q->pi_state;
-       u32 uval, curval, newval;
        struct task_struct *oldowner, *newowner;
-       u32 newtid;
-       int ret, err = 0;
-
-       lockdep_assert_held(q->lock_ptr);
-
-       raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+       u32 uval, curval, newval, newtid;
+       int err = 0;
 
        oldowner = pi_state->owner;
 
@@ -2376,14 +2371,12 @@ retry:
                         * We raced against a concurrent self; things are
                         * already fixed up. Nothing to do.
                         */
-                       ret = 0;
-                       goto out_unlock;
+                       return 0;
                }
 
                if (__rt_mutex_futex_trylock(&pi_state->pi_mutex)) {
                        /* We got the lock. pi_state is correct. Tell caller. */
-                       ret = 1;
-                       goto out_unlock;
+                       return 1;
                }
 
                /*
@@ -2410,8 +2403,7 @@ retry:
                         * We raced against a concurrent self; things are
                         * already fixed up. Nothing to do.
                         */
-                       ret = 1;
-                       goto out_unlock;
+                       return 1;
                }
                newowner = argowner;
        }
@@ -2442,7 +2434,6 @@ retry:
         * itself.
         */
        pi_state_update_owner(pi_state, newowner);
-       raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 
        return argowner == current;
 
@@ -2465,17 +2456,16 @@ handle_err:
 
        switch (err) {
        case -EFAULT:
-               ret = fault_in_user_writeable(uaddr);
+               err = fault_in_user_writeable(uaddr);
                break;
 
        case -EAGAIN:
                cond_resched();
-               ret = 0;
+               err = 0;
                break;
 
        default:
                WARN_ON_ONCE(1);
-               ret = err;
                break;
        }
 
@@ -2485,17 +2475,26 @@ handle_err:
        /*
         * Check if someone else fixed it for us:
         */
-       if (pi_state->owner != oldowner) {
-               ret = argowner == current;
-               goto out_unlock;
-       }
+       if (pi_state->owner != oldowner)
+               return argowner == current;
 
-       if (ret)
-               goto out_unlock;
+       /* Retry if err was -EAGAIN or the fault in succeeded */
+       if (!err)
+               goto retry;
 
-       goto retry;
+       return err;
+}
 
-out_unlock:
+static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+                               struct task_struct *argowner)
+{
+       struct futex_pi_state *pi_state = q->pi_state;
+       int ret;
+
+       lockdep_assert_held(q->lock_ptr);
+
+       raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+       ret = __fixup_pi_state_owner(uaddr, q, argowner);
        raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
        return ret;
 }